Search Results (29)

Electrochemical treatment can provide contaminant destruction, phase separation, ionic polishing, and resource recovery; however, performance cannot be judged by removal efficiency alone. This structured critical review compares electro-oxidation (EO), electrocoagulation (EC), electro-Fenton (EF), electrodialysis (ED), electrodeionization (EDI), capacitive deionization (CDI), flow-electrode CDI (FCDI), and bioelectrochemical systems (BES) in municipal wastewater, industrial effluents, sludge-related applications, and treatment side-streams. Searches of Scopus, Web of Science Core Collection, and PubMed were updated to 22 July 2026, and the evidence was assessed according to treatment function, wastewater realism, operating mode, durability, residual fate, energy and cost boundaries, resource recovery, and life cycle implications. Recent advances include porous flow-through anodes, oxygen-efficient cathodes, selective ion separation materials, and pilot BES configurations. However, scale-up remains constrained by electrode aging, by-products, sludge and concentrate management, oxygen transfer, fouling, competing ions, internal resistance, biological instability, and incomplete long-term economic and environmental evidence. The quantitative results show that the energy, cost, and carbon outcomes depend strongly on the treatment function and system boundary. The evidence for sludge and biosolids is less mature than that for liquid wastewater. Therefore, electrochemical technologies are best positioned as function-specific units within hybrid treatment trains rather than as universal replacements for conventional treatments. Full article

Re-establishing native plant communities is critical for restoring post-mine influenced sites. A major challenge is that mining activity can result in poor soil quality that is not conducive to plant growth. Various soil amendments can provide organic material and nutrients that assist plant growth. Biosolids, treated solids recovered from municipal wastewater, can be used as a soil amendment to improve soil quality of mine-influenced landscapes and provide the nutrients for plant growth. The objectives of this study were (1) to determine an appropriate rate of biosolid application to promote the colonization of native plants and (2) to determine the effects of the biosolids on soil properties. In 2021, a field study was devised that tested four biosolid application rates (0, 125, 250, and 375 dry Mg/ha). The site was located in a mining area in the southern interior of British Columbia, Canada, with six replicates per experimental combination. This study demonstrated that biosolids significantly increased the productivity and diversity of the plant community. Biosolids reduced soil pH and increased soil organic matter, carbon and nitrogen concentrations. Receiving soils were either similar to or marginally high in arsenic (As) and molybdenum (Mo). In contrast, biosolids tended to significantly increase Cu levels compared to the control soils. Higher rates of biosolids did not lead to significantly higher plant productivity or diversity than the lower rates. The results of this study suggest that biosolids may significantly help restore sustainable grassland ecosystems in post-mining environments even at a lower application rate of 125 dry Mg/ha. Full article

Pharmaceuticals are essential to modern healthcare but increasingly represent a pervasive and biologically active class of environmental contaminants. Following administration, many drugs are incompletely metabolised in the human body and are excreted as parent compounds or active metabolites, subsequently entering municipal wastewater treatment plants (WWTPs). Conventional treatment processes only partially remove many pharmaceuticals, resulting in chronic sub-therapeutic exposure of microbial communities which act as both functional agents of biodegradation and sensitive ecological targets. Such exposure alters microbial structure and function, reduces biotransformation capacity, promotes the persistence of recalcitrant compounds such as carbamazepine and diclofenac, and drives the selection and dissemination of antibiotic resistance genes. These effects may propagate across aquatic, terrestrial, agricultural, and food systems via treated effluents and biosolids, linking human medical practices to environmental and public health outcomes. By integrating Pharmaceutical science, wastewater engineering, microbiome ecology, and antimicrobial resistance research, this work frames pharmaceutical pollution as a closed-loop OneHealth challenge. Full article

Biodegradable waste is commonly treated as a problem to be managed, but it can be a valuable resource when considered within a circular bioeconomy perspective. This article develops a practical and systems-based frame work for integrating biodegradable waste, ranging from municipal food scraps to wastewater biosolids, into valuable resources. It explores real-world strategies for transforming waste into value-added products, including composting, anaerobic digestion, biochemical conversion, and the creation of bio-based materials. The review also highlights key drivers and barriers, including technical, regulatory, and social factors, which shape the feasibility and impact of circular solutions. A visual model illustrates the full cycle, from identifying waste streams to reintegrating recovered resources. The paper also highlights case studies from Toronto, Milan and Brazil as examples of successful implementation. Overall, this paper emphasizes a pragmatic yet regenerative shift toward organic resource recovery aligned with sustainability and decarbonization goals. Full article

Societies are aiming to have a higher ecological consciousness in wastewater treatment operations and achieve a more sustainable future. With this said, global demands for larger quantities of resources and the consequent waste generated will inevitably lead to the exhaustion of current municipal wastewater treatment works. The utilization of biosolids (particularly microbial proteins) from wastewater treatment operations could generate a sustainable bio-adhesive for the wood industry, reduce carbon footprint, mitigate health concerns related to the use of carcinogenic components, and support a more circular economic option for wastewater treatment. A techno-economic analysis for three 10 MGD wastewater treatment operations producing roughly 11,300 dry pounds of biosolids per day, in conjunction with co-feedstock defatted soy flour protein at varying ratios (i.e., 0%, 15%, and 50% wet weight), was conducted. Aspen Capital Cost Estimator V12 was used to design and estimate installed equipment additions for wastewater treatment plant integration into an urban biorefinery process. Due to the mechanical attributes and market competition, the chosen selling prices of each adhesive per pound were set for analysis as USD 0.75 for Plant Option P1, USD 0.85 for Plant Option P2, and USD 1.00 for Plant Option P3. Over a 20-year life, each plant option demonstrated economic viability with high NPVs of USD 107.9M, USD 178.7M, and USD 502.2M and internal rates of return (IRRs) of 24.0%, 29.0%, and 44.2% respectively. The options examined have low production costs of USD 0.14 and USD 0.19 per pound, minimum selling prices of USD 0.42–USD 0.51 per pound, resulting in between 2- and 4-year payback periods. Sensitivity analysis shows the effects biosolid production fluctuations, raw material market price, and adhesive selling price have on economics. The results proved profitable even with large variations in the feedstock and raw material prices, requiring low market selling prices to reach the hurdle rate of examination. This technology is economically enticing, and the positive environmental impact of waste utilization encourages further development and analysis of the bio-adhesive process. Full article

Water scarcity has affected much of Chile for the past 15 years, and Amelichloa caudata, a native species adapted to arid conditions, may offer a solution. The hypothesis of this study is that both acetylsalicylic acid (ASA) and biosolids (BSs) can positively influence plant growth under water stress. This study assessed the effects of ASA and BSs on edaphic, physiological, biochemical, and productive parameters of A. caudata under water scarcity conditions. Results showed that both treatments enhanced biomass production, plant height, leaf number, and canopy weight. ASA improved water retention, mitigating water stress effects and leading to biomass levels comparable to controls. In contrast, BSs did not show significant benefits and had the lowest biomass values under all conditions. The highest root dry weight was observed in water-restricted plants, while ASA-treated plants had lower malondialdehyde (MDA) levels, indicating reduced oxidative stress. However, BS treatment increased MDA levels, suggesting more severe oxidative damage. Despite improvements in water retention, high salt concentrations in BSs may limit their effectiveness and further research is required to optimize application rates. Full article

Phytostabilization of metals involves the inactivation of metals in the soil through the use of various materials as soil amendments, which reduces the bioavailability of metals, and then the introduction of vegetation. There are limited data comparing the effectiveness of different phytostabilization amendments under the same soil and environmental conditions. Therefore, the aim of this research was to compare the effectiveness of a range of soil amendments on reducing the extractability of metals, metal uptake by plants, microbial activity in soil and nutrient availability to plants. Eight materials potentially limiting metal availability were used in a pot experiment: two composts (CG, CM), municipal biosolids (SB), bentonite (BEN), phosphorus fertilizer (PF), amorphous iron oxide (FE), waste rock material (WR), calcium carbonate (LM); and these materials were compared with typical fertilization (NPK) and an untreated soil as the control (CTL). The following trace metal-contaminated soils were used in the pot experiment: soil taken from the area of strong dust fall from the zinc and lead smelter (soil P); soil taken from an outcrop of ore-bearing rocks near a smelter waste heap (soil H); soil artificially polluted through smelter dust spill in the 1990s (soil S). In general, the greatest yields of plants (oat and white mustard) were recorded for compost-treated soils. Changes in the solubility of zinc (Zn) and cadmium (Cd) after the application of various amendments largely reflected changes in soil pH. Biosolids caused a significant increase in extractable Zn and Cd, which was related to the decrease in soil pH, while a significant reduction in Cd extractability was observed across soils after the application of both composts, especially the compost characterized by alkaline pH. Interestingly, low extractability of Cd in the soil with the addition of another compost was observed, despite the pH decrease, as compared to the control pots. This fact proves the high sorption capacity of the compost towards Cd. The microbiological analyses revealed the highly beneficial effect of composts for dehydrogenases and nitrification activities, and for soil respiration, whereas soil amendment with iron oxide caused an increase in respiration activity across soils. Full article

The continuous development of drinking water networks is leading to the production of increasing amounts of waste water and sewage sludge. Secondary-treated sewage sludge is called biosolids and can be used as fertilizers in agriculture due to its rich nutrient content. The aim of this study was to evaluate the effects of biosolids mixed with an eroded soil on the morphology, physiology and synthesis of bioactive compounds in basil. The study was performed in pots under laboratory-controlled conditions. In total, four substrates were tested: S1 biosolids 100%, S2 biosolids 15% + eroded soil 85%, S3 eroded soil 100% and S4 control (commercial growing substrate). At the morphological level, a significant increase in plant height, number of branches, fresh biomass and dry biomass was found in the S2 variant. At the physiological level, photosynthesis and chlorophyll content did not vary significantly, but the quantum yield of PSII (ΦPSII) was significantly higher at S1 and S2. The oxidative status evaluated by determining the activity of SOD, POD and CAT enzymes was better in S2 and S3 compared to S3. Regarding the synthesis of bioactive compounds (rosmarinic acid, caffeic acid and gallic acid), it was stimulated in S1 and S2. In conclusion, biosolids application stimulated the stress response mechanisms in basil plants by increasing the quantum yield chlorophyll fluorescence and catalase activity, alleviating the negative effects of eroded soil. Full article

Challenges associated with mesophilic digestate (MD) involve volume, odor, and pathogens, which effective post-digestion treatments can address. The efficiency of MD post-treatment can be enhanced by conditioning with ferric chloride (FeCl₃), hydrogen peroxide (H₂O₂), and polymer. This study aimed to observe the effect of combined chemical conditioning on volume reduction, phosphorus (P) release, odor, and pathogen reduction potential for MD. MD was conditioned with polymer only, polymer and FeCl₃ at pH adjusted to 8.0 with lime (Ca(OH)₂), and a blend of polymer, FeCl₃, and hydrogen peroxide (H₂O₂) at pH 8.0. The results show that adding all three chemicals improved post-treatment efficiency at 2.1 kg/t DS FeCl₃, 2.1 kg/t DS polymer, and 600 mg/L H₂O₂ at pH 8.0, compared with polymer or dual conditioning. At the combined dose, cake solid content, centrate P removal, and odor reduction capability improved compared with raw MD by 20%, 99%, and 66%, respectively. Combined chemical treatment reduced fecal coliform by 98% but does not fulfil class A requirements and showed 50% regrowth potential. The synergic effect of polymer, FeCl₃, H₂O₂, and alkaline pH breakdown EPS, reduced water holding capacity and formed compacted flocs for better water removal and settling. This combination also precipitated P through FeCl₃ while H₂O₂ oxidation curbs odor, enhancing further P removal from centrate. Full article

Composting is widely used to recycle a variety of different organic wastes. In this study, dairy manure, chicken litter, biosolids, yard trimmings and food waste were selected as representative municipal and agricultural feedstocks and composted in simulated thermophilic composting reactors to compare and evaluate the GHG emissions. The results showed that the highest cumulative emissions of CO₂, CH₄ and N₂O were observed during yard trimmings composting (659.14 g CO₂ kg⁻¹ DM), food waste composting (3308.85 mg CH₄ kg⁻¹ DM) and chicken litter composting (1203.92 mg N₂O kg⁻¹ DM), respectively. The majority of the carbon was lost in the form of CO₂. The highest carbon loss by CO₂ and CH₄ emissions and the highest nitrogen loss by N₂O emission occurred in dairy manure (41.41%), food waste (0.55%) and chicken litter composting (3.13%), respectively. The total GHG emission equivalent was highest during food waste composting (365.28 kg CO₂-eq ton⁻¹ DM) which generated the highest CH₄ emission and second highest N₂O emissions, followed by chicken litter composting (341.27 kg CO₂-eq ton⁻¹ DM), which had the highest N₂O emissions. The results indicated that accounting for GHG emissions from composting processes when it is being considered as a sustainable waste management practice was of great importance. Full article

Municipal sewage sludge is the residual material produced as a waste of municipal wastewater purification. It is a sophisticated multi-component material, hard to handle. For many years, it has been landfilled, incinerated, and widely used in agriculture practice. When unproperly discharged, it is very polluting and unhealthy. The rapidly increasing global amount of municipal sewage sludge produced annually depends on urbanization, degree of development, and lifestyle. Some diffused traditional practices were banned or became economically unfeasible or unacceptable by the communities. In contrast, it has been established that MSS contains valuable resources, which can be utilized as energy and fertilizer. The objective of the review was to prove that resource recovery is beneficially affordable using modern approaches and proper technologies and to estimate the required resources and time. The open sources of information were deeply mined, critically examined, and selected to derive the necessary information regarding each network segment, from the source to the final point, where the municipal sewage sludge is produced and disposed of. We found that developed and some developing countries are involved with ambitious and costly plans for remediation, the modernization of regulations, collecting and purification systems, and beneficial waste management using a modern approach. We also found that the activated sludge process is the leading technology for wastewater purification, and anaerobic digestion is the leading technology for downstream waste. However, biological technologies appear inadequate and hydrothermal carbonization, already applicable at full scale, is the best candidate for playing a significant role in managing municipal sewage sludge produced by big towns and small villages. Full article

This study evaluated biosolid quality over time and the efficiency of using amounts (5 and 7 kg/m²) of municipal class A biosolids in Qatar to fertilize tomato plants (Solanum lycopersicum). Random samples were subjected to physical and chemical analysis, which revealed excellent particle uniformity and stability with minor odor defects. The analysis confirmed the product was nutrient-rich while pollutant levels were below the international standards. The nominated rates were used to fertilize tomato plants in pots grown in a greenhouse for four months with a control treatment of manure and Peat-Moss, before measuring the plant biological characteristics. Plants were examined via chemical analysis of nutrients and pollutants both for the whole plant and for stems, fruits, and leaves. Results indicated that both experimental treatments enhanced plant growth and development as compared to the control treatment. However, the chemical analyses also revealed levels of zinc, copper, and manganese in the plant fruits that were well in excess of the maximum acceptable levels, as defined by international health organizations. This study found that while the application of class A biosolids as organic fertilizer for tomato plants greatly enhanced the overall plant growth, the plant fruits contained toxic levels of trace heavy metals. Full article

The difficulties in the management and use of biosolids in Colombia make it necessary to evaluate and analyze the factors involved through various methodologies to achieve the effective management and recycling of this type of waste. The objective of this study was to evaluate the management of sludge and biosolids from a WWTP in a Colombian municipality through the application of three methodologies (SWOT/TOWS, surveys, and stakeholder (player) weighing) for their subsequent use in agriculture. As a result, strategies were proposed at the regulatory, organizational policy, and entity integration levels, among others. It was identified that about 93.6% of the people surveyed had a positive attitude towards the use of biosolids in agriculture, despite recognizing the existence of a risk (27.3%) in this type of practice. On the other hand, regarding the communication of WWTP management of these wastes, they perceived that it to be absent (65%) and the lack of knowledge regarding the destination of these wastes was even greater (72.7%). Through the weighting of actors, 16 players were classified with whom it is necessary to work closely, regularly, or occasionally. The methodologies proposed will allow similar WWTPs to optimize their processes through continuous improvement and joint work between the different entities and communities. It is recommended that other methodologies be used to evaluate player position level in relation to planned strategies, as well as the level of associations of one player with another, independent of power and influence. Full article

This study was conducted to evaluate the effect of three different rates of municipal biosolids produced in Qatar on plant characteristics and soil texture and its potential impacts on groundwater. Petunia atkinsiana, was used in this study. The experiment took place in a greenhouse in pots with soil mixed with 0, 3, 5, and 7 kg/m² biosolids. Pelletized class A biosolids from the Doha North Sewage Treatment Plant were used. Results revealed significant differences in all measured parameters, which were affected by biosolid treatments compared to the control treatment. Electrical conductivity, pH, macro and micronutrients and heavy metals were significantly affected by biosolid treatments. The comparison of the discovered levels against the international acceptable ceilings of pollutants indicated the advantages of utilizing class A biosolids, as they were well below the international acceptable levels and showed the best test rates, indicating that the product is a sustainable and efficient organic fertilizer for ornamental plants. Furthermore, the results highlight no potential significant impacts on groundwater due to trace presence of heavy metals, owing to the nature of deep groundwater in Qatar and the usage of modern irrigation devices that fulfil the exact needs of plants in a harsh climate and high evaporation rate. Full article

This paper is a review of 20 years of full-scale experience with the granular sludge-based ANAMMOX process. The ANAMMOX process is a biological deammonification process for energy-efficient removal of ammoniacal nitrogen, which has been successfully applied on dewatering reject liquors from biosolids sludge digesters (e.g., mesophilic anaerobic digestions, codigestion, thermal sludge hydrolysis process (THP)) and nutrient-rich anaerobically treated industrial effluents (e.g., fermentation industry, food industry). The ANAMMOX process is a continuously operated biological process using granular biomass. The highly active concentrated granular biomass allows for compact reactor systems and a fast start-up. Long term operations of various case studies show stable process performance of full-scale reactors treating municipal and industrial effluents, achieving ammoniacal nitrogen (NH₄-N) removal in excess of 90% at low and high loading rates up to 2.5 kgNH₄-N/(m³·d). Some special aspects (e.g., micro-nutrients, inhibition, alkalinity consumption) of treating various wastewaters are discussed in detail. The ANAMMOX process is demonstrated to be resilient in handling process upsets and off-spec wastewater composition. Full article